Liquid trough seal



Feb. 6,1968 T. E. BAN 3,367,644'

LIQUID TROUGH SEAL Filed Feb. '7, 1966 Fig, 3

THOMAS E. BAN

@YM MW ATTORNEYS IN VEN TOI? v United States Patent O 3,367,644 LIQUIDTROUGH SEAL Thomas E. Ban, Cleveland Heights, Ohio, assigner toMclowell-Wellman Engineering C0., a corporation of hio Filed Feb. 7,1966, Ser. No. 525,775 15 Claims. (Cl. 263-28) ABSTRACT F THE DISCLSUREA flexible strip used in conjunction with a liquid seal comprising atrough partially illed with liquid and a llange extending from a movingpallet into the trough and liquid intermediate the sides of the trough,for transversely sealing the space between the flange and an adjacenttrough side to keep fluid under pressure from passing through saidspace.

This invention is especially well suited for use in a circular travelinggrate machine having adjacent zones in which gas pressure and vacuum ortwo dilferent gas pressures are maintained. The following description,therefore, will be in relation to such a traveling grate machine.

The circular traveling grate machine essentially comprises, a pluralityof pallets movable along a generally circular path and in the same planewhich is normally horizontal. The pallets move between a hood which isxedly surmounted in spaced relation from a windbox. A liquid seal suchas described in Patent No. 3,302,936 is utilized to seal the spacebetween the windbox, moving pallets and hood. Such a seal, for example,employs a trough mounted on each marginal edge of the windbox and hoodadjacent the moving pallets. Liquid, e.g. water, is circulated in thetrough. The pallets carry a flange at each marginal edge. The palletflanges are configured to extend into the trough for sealing engagementwith the circulating liquid. Thus, the space between the windbox, hood,and moving pallets is closed forming an envelope which is sealed fromthe ambient atmosphere.

A problem exists when, for example, gases under pressure are passed fromone section of the windbox upwardly through a burden on the pallets, andthen recirculated downwardly through the burden on the pallets into anadjacent section of the windbox, as a channel is formed in the troughbetween the llange and the trough side adjacent the pallets. The gaseswill circulate through the channel between the adjacent zones, orwindbox sections rather than move through the burden on the movingpallets. In other words, the gases will short circuit through thechannels formed in the troughs, the movement of the gases through thechannels being the path of least resistance. This short-circuiting ofthe gases is detrimental to 'processing the burden on the movingpallets. This invention is directed to providing a seal for blockingthis channeling of the gases through the troughs between adjacent hoodor windbox sections under differential iluid pressure, or fluid pressureand vacuum.

Briefly stated, the invention is in a flexible or pliable sealing stripmounted in the trough for sealing engagement with the flange extendinginto the trough, and the trough side adjacent the pallets. The sealingstrip is provided between adjacent zones in which gas pressure andvacuum, or two different gas pressures are maintained.

The following description of the invention will be better understood byhaving reference to the annexed drawing, wherein:

FIG. 1 is a cross-sectional View of a conventionallydesigned circulartraveling grate machine comprising a windbox, pallets and hood, andemploying a trough-type liquid seal for sealing the spaces between themarginal edges of the windbox and hood, and moving pallets;

FIG. 2 is an enlarged sectional view of a typical trough secured to, forexample, the marginal edge of the windbox, and a flange carried, forexample, by the pallets for sealing coaction with the liquid in thetrough, and illustrating an embodiment of the invention for sealing thechannel formed in the trough; and

FIG. 3 is a fragmentary top sectional View showing the embodiment of theinvention of FIG. 2 in cross section.

Referring more particularly to FIGS. 1-3 of the annexed drawing, thereis shown a circular traveling grate machine generally indicated at 10.The traveling grate machine 10 essentially comprises a. hood 11 lixedlysurmounted in spaced relation from a windbox 12. A plurality of pallets,e.g. pallet 13, are movable between the hood 11 and windbox 12.Eachpallet is mounted on wheels which are movable along a trackwaymounted outside the windbox 12 and hood 11, e.g. the wheels 14 and 1S ofpallet 13, are movable along the trackway rails 16 and 17 outside andadjacent the windboxs marginalv edges 18 and 19.

The following description of the invention will be in relation to atrough 2d and ange 21 mounted on the windbox 12 and pallet 13,respectively, it being understood that the inventive concept isapplicable to other troughs and flanges used.

The particular design of the trough is important. The trough should beof suflicient width and depth such that the volume of liquid in thesection of the trough between the flange and the trough side farthestfrom the pallets, is at least about four to live times the volume ofliquid in the section of the trough between the llange and the troughside adjacent the pallets. If the reservoir of liquid in the formermentioned section of the trough is insufflcient, it is diicult tomaintain a satisfactory vacuum within the windbox. Also, gases passingthrough the burden on the grates of the pallets, under pressure canescape from the process by bubbling through the insuflicient liquidreservoir in the trough.

lnventve concept A-lluid passageway or channel 25 is formed in thetrough 20 between the dip portion 26 of the flange 22, or that portionof the ange extending into the trough 21, and the trough side 27adjacent or closest the pallets when gas pressure and vacuum, ordifferential gas pressures are maintained in adjacent windbox sections,e.g. sections 23 and 24. In such cases, the gases for carrying Iout theprocess, will circulate through the iluid passageway 25 rather than passthrough the burden on the pallets. Under such conditions of gas pressureand vacuum, for example, a liquid head 28 (shown in dotted line) mayresult in that portion or section A of the trough 20 adjacent thewindbox section 24 under gas vacuum, and a comparatively smaller liquidhead 29 (shown in dotted line) may result in that portion or section Bof the trough 20 adjacent the windbox section 23 under gas pressure. Thetrough should be designed such that a relatively constant head orreservoir of liquid 30 (shown in dotted line) can be maintained in thatportion or section C of the trough 20 between the pallet dip flange 26and the opposing trough side 31. If, for example, vthe reservoir ofliquid 30 would closely approach the head of liquid 29 under gaspressure, gas under pressure could bubble through the liquid in sectionsB and C, and escape from the process.

A sealing strip 32 is provided to seal the passageway or channel 25. Thesealing strip 32 is at least coextensive with the dip flange portion 26aextending into the trough 20, and, preferably, extends to the troughbottom 33 and the pallet, which in this case is the lateral flangeportion 34 extending from the pallet. The sealing strip 32, preferably,covers the area defined by the trough bottom 33, the lateral palletflange 34, the pallet dip flange 26, and the trough side 27. In thismanner, the passageway or channel formed between the trough side 27 andthe pallet dip flange 26, is effectively sealed or blocked.

The sealing strip 32 is, preferably, flexible or pliable, and composedof any suitable gas or liquid impervious material, eg. rubber, plasticor metaL'The flexible sealing 32 is designed to compressively engage thedip flange 26 and trough side 27. This can be accomplished by,preferably, ydetachably mounting the flexible sealing strip 32 on thetrough side 27 by any suitable fastening means, e.g. bolts 35. Thesealing strip 32 is, preferably, rolled; that is, it is generallyU-shaped, which permits the sealing strip 32 to expand or contract inorder to compressively engage the dip flange 26, as it moves laterallytowards rand away from the trough side 27, such movement being caused,for example, by misalignment of the pallets as they move along thetrackway.

Conventionally designed dead plates are normally mounted on theadjoining edge 36 of the adjacent windbox sections 23 and 24 forengaging the underside of the pallets, e.g. underside 37 or pallet 13,to restrict movement of the gas through the space between the adjoiningedge 36 of the adjacent windbox sections 23 and 24, and the underside ofthe pallets. In some pallet designs, the dead plates traversing thewidth of the pallets and windbox sections, may extend to the troughsides, in which case the sealing strip 32 would compressively engage theadjacent dead plate to seal or block the fluid passageway formed by thetrough, pallet and said adjacent dead plate.

Thus, there has been provided a new and novel means for sealing achannel formed in the trough of a troughtype liquid seal employing aflange extending into a trough partially fllled with liquid. Such meansare essential for keeping, for example, the gases un'der pressure, fromby-passing into a next adjacent zone under less gas pressure, or gasvacuum, rather than passin-g throu-gh a burden on the pallets.

Other modes of applying the principle of this invention may be employedinstead of those specifically set forth above, changes being made asregards the details herein disclosed, provided the elements set forth inany of the following claims, or the equivalent of such be employed.

It is, therefore, particularly pointed out and distinctly claimed as theinvention:

1. In combination:

(a) at least two adjacently disposed windbox sections;

(b) a hood in fixed surmounted spaced relation to the windbox sections;

(c) a plurality of pallets movable between the windbox sections andhood;

(d) trough-type liquid seals coacting between the pallets, hood andwindbox sections to seal the spaces between the marginal edges of thehood and windbox sections and the moving pallets; and

(e) means for transversely sealing a channel formed in each troughbetween a flange extending into the liquid in the trough and the side ofthe trough adjacent the pallets, to prevent gas under pressure frompassing between the windbox sections through the channel, rather thanthrough a burden carried by the pallets.

2. The combination of claim 1, wherein the channel sealing meansincludes a flexible sealing strip mounted for compressively engaging thetrough side adjacent the moving pallets and the flange extending intothe liquid in the trough.

3. The combination of claim 2, wherein the sealing 4 strip is mounted onthe trough side adjacent the moving pallets.

4. The combination of claim 3, wherein the flexible sealing strip is atleast coextensive with the depth of the flange extending into thetrough.

5. The combination of claim 4, wherein the flexible sealing strip isrubber.

6. In a seal comprising a trough at least partially filled with liquidand a flange extending into the trough and liquid intermediate the sidesor the trough, the improvement which comprises a flexible strip disposedin sealing relation with the flange, liquid and an adjacent trough sidefor transversely sealing the space between the flange, liquid andadjacent trough side to keep fluid under pressure from circulatingthrough said space.

7. In a seal having a plurality lllled with liquid, and a flangeextending into the trough and liquid intermediate the sides of thetrough; the improvement which comprises means for transversely sealingthe space between the flange, and an adjacent trough side to keep gasunder pressure from circulating through said space, said means includinga flexible sealing strip at least coextensive with the depth of theflange in the trough and compressively engaging the llange and adjacenttrough side.

8. The improvement of claim 7, wherein the sealing strip is configuredto compressively engage the `flange and trough side should the flangeand trough side move relatively towards and away from each other.

9. The improvement of claim 8, wherein the flange moves and the troughis stationary, and the sealing strip is mounted on the trough side.

10. The improvement of claim 9, wherein the sealing strip is rubber.

11. In a circular traveling grate machine including a plurality ofpallets moving sequentially across at least one pair of adjacentlydisposed windboxes in which differential gas pressures or gas pressureand vacuum are maintained; means for sealing the spaces between thewindboxes and moving pallets, including:

(a) a trough mounted on the opposing marginal edges of the windboxes,and partially filled with liquid;

(b) a flange carried by the pallets at each marginal edge, andconfigured to extend into the trough and liquid to seal the spacebetween the marginal edges of the pallets and windboxes, the flangeextending into the trough intermediate the sides of the trough; and

(c) means for sealing a by-passageway formed by the trough, pallets andflange, through which the gas can circulate between the windboxes ratherthan pass through a burden on the pallets moving across said windboxes,

12. The space sealing means of claim 11, wherein the gas by-passagewaysealing means includes:

(d) a flexible sealing strip mounted to compressively engage the flangeand trough side adjacent the pallets.

13. The place sealing means of claim 12, wherein the flexible sealingstrip is mounted on the trough side adjacent the pallets, and is atleast coextensive with the depth of the flange in the trough.

14. The space sealing means of claim 13, wherein the sealing strip iscomposed of a gas impervious material.

15. The space sealing means of claim 13, wherein the sealing strip iscomposed of rubber.

References Cited UNITED STATES PATENTS 8/1959 Matis et al. 263--284/1965 Sims et al 34--242 X

